Substance use disorders (SUDs) continue to be one of the most serious public health problems in the US. Studies have consistently documented a substantially higher prevalence of SUDs among individuals under criminal justice supervision. At year-end 2013, approximately 4.75 million adults were on probation or parole (1 in 51 adults). African American probationers and parolees with SUDs are particularly vulnerable to illicit substance use and HIV infection as they typically live in neighborhoods characterized by high rates of joblessness, drug use, and poverty and they are likely to engage in drug-and sex-related HIV risk behaviors in the community. Studies have shown that continuing care interventions have been found to extend primary treatment gains with respect to reductions in substance use, relapse, and criminal activity. We propose to develop a continuing care mobile application for probationers and parolees completing substance abuse treatment who are at high risk of substance abuse relapse, HIV related risk factors, and re-arrest and re- incarceration. Probationers and parolees, many of whom are low-income urban African Americans, are an important health disparity population that stands to benefit from continuing care technologies. This research will be conducted in collaboration with Total Health Care (THC), a federally qualified health center and Maryland's largest minority-operated non-profit community health center. If found effective, the proposed application could be deployed across the national network of outpatient substance abuse treatment providers/programs, potentially improving the dissemination of continuing care services outside of traditional systems of care and be highly significant in its direct impact on public health for individuals involved in the criminal justice system.